A motor vehicle conveyance component of particular interest is a semi-trailer conveyance component of heavy-duty trucks, wherein a driver operated tractor is selectively connectable thereto. In this regard, the semi-trailer is composed of a deck (floor) having a peripheral lower side-rail and a roof having a peripheral upper side-rail. Between the upper and lower side-rails are left and right sidewalls, a front wall and left and right doors, each door being hinged to a respective one of the left and right sidewalls.
Referring now to FIGS. 1A and 1B, the operation of the doors of a semi-trailer 10 will be discussed. The left and right doors 12L, 12R are held in a closed state by one or more latch rods 14, which interfacingly seat with respect to the upper and lower side-rails of the semi-trailer 10 to hold the doors securely closed for over the road transportation. When the time comes to load or unload the semi-trailer, the latches are unseated with respect to the upper and lower side-rails, and the left and right doors swung open on hinges connected to the respective left and right sidewalls of the semi-trailer 10.
An open doors situation requires a great deal of care, in that the wind could catch a door and cause it to pivot undesirably, even dangerously. Additionally, it is necessary for the left and right doors to be kept in a fully open state, wherein the doors are adjacent their respective left and right sidewalls, as a semi-trailer is backed into the dock opening at a truck depot facility so as to avoid damage caused by impact of a partially open door with the dock opening or an adjacent structure, such as for example another semi-trailer.
The solution long adopted by the trucking industry is to secure the doors in a fully open state via a mechanical open door retainer 18 in the form of either a chain or a bungee which is selectively secured to the lower side-rail. In the operative example shown at FIG. 1B, a chain 18a is full-time secured respectively to each of the left and right doors, and the free end thereof secured to a hook 18b located at the lower side-rail 16 of the respective left and right sidewalls (the left sidewall 20L being shown at FIG. 1B).
While a conventional mechanical open door retainer does provide retention of the doors in the fully open state, there are a number of drawbacks and/or problems associated with it. One major problem is that the semi-trailer operator must make a conscious effort to secure operation of a mechanical open door retainer, its operation is not automatic. Other disadvantages and/or problems include: the chains or bungees may loosely swing during over the road transportation; the hook may become bent, obstructed by ice or debris, or become otherwise inoperable; the chains are often broken when the door is forced open rendering them useless; the chains or bungees may shake loose when fork lifts drive into and out of the semi-trailer thereby allowing the doors to slam back and forth against the sidewalls, or adjacent structure, as a forklift moves in and out, the truck is moving or is buffeted by wind.
Accordingly, it would be a very advantageous advance of semi-trailer trucking technology if somehow an open door retainer could be devised which operated automatically and has none of the problems or disadvantages of the present mechanical open doors retainer. In addition, it would be advantageous if the aforesaid open door retainer had application to all manner of conveyance components used in the motor vehicle arts, including for example and without limitation, trailers, shipping containers, delivery vans, covered utility trailers, moving vans, wagons, etc.